In certain clinical settings it is necessary to implant an aortic valved tube which, incorporating a cardiac valvular prosthesis, is used to replace the aortic valve and the aorta itself in its ascending path.
These clinical settings are known by the following names:
"Acute dissection of the ascending aorta"
"Marfan's syndrome"
"Traumatic breakage of the ascending aorta affecting the aortic valve and the right and left coronary arteries."
Surgical treatment of these clinical settings dates back some fifty years, during which techniques and methods, as well as the implant models, have improved, though a suitable physiological model has not been attained up to now.
In this sense, the first attempts were made by implanting a tube made out of special fiber, replacing the torn or broken aorta sector, without replacement of the aortic valve.
Subsequently, implant models with the valvular prosthesis incorporated in the tube came about, and this is the present situation.
On the other hand, the anatomico-pathological setting of acute dissection of the ascending aorta can be summarized in the following: upon producing breakage of the intima layer of the aorta, blood penetrates in the thickness of the layers of said artery, making a dissection among them, causing hemorrhage and compression.
Almost always associated with this problem is an aortic bicuspid valve, of congenital origin, heeding replacement.
The clinical setting is completed with the dislocation of the coronary arteries and, at times, with dissection thereof.
This clinical setting is necessarily dramatic and fatal if surgical repair is not rapidly and urgently done.
Said surgery is based on "reconstruction" of the aortic valvular ring of the involved after and "reimplantation" of the coronary arteries: right and left.
The implant element in the surgery is the above cited aortic valved tube, which comprise a single tube with a cardiac valvular prosthesis implanted inside it, and in correspondence with the proximal end thereof.
When using this aortic valved tube, upon having to "reimplant" the left and right coronary arteries, two holes must be made in the wall of the valved tube, and these holes must be "adapted" to the holes of the ostiums of the corresponding coronary arteries.
Such operations involve the difficulties that the holes made in the wall of the valved tube may not be uniform with their surroundings, aside from having a weak structure.
On the other hand, anastomosis causes distortion of the tube, leaving a residual "asymmetric" traction.
As a result of this, hemorrhage is frequent and, many times, it is the main cause of post-operative death in this type of surgery.
It is also to be taken into account that when the dissection has been very great and the coronary arteries have been greatly dissected, it is practically impossible to carry out anastomosis from a technical point of view, such procedure produces distortion of the valved tube, with the subsequent defect of the suture, with undue tractions, with alterations in the bloodstream, as well as distortions in the functioning of the prosthesis incorporated in the valved tube.
Finally, it should be said that by means of said known aortic valved tube, the patient's aortic valvular problem is corrected, as well as the ascending aorta section implicated in the breakage. Now then, there is no doubt that the ostiums of the coronary arteries must still be "brought near" the valved tube, where said two holes have to be made in order to be able to bring it close to the edges of the coronary ostiums. Upon effecting said operation, breakage of the integrity of the tube, of its structure, is produced, likewise producing on many occasions small dilacerations which later produce tearing and cause hemorrhaging.
On the other hand, because it is practically impossible that the holes be made symmetrically, asymmetric tractions will be produced which distort the location of the tube, with the subsequent detriment to its functioning will be produced.
In the case of hemorrhage, once the tube has been implanted and the coronary arteries have been coupled, it becomes very complicated and difficult to act with surgical delicateness when necessary to give some additional stitches and, generally, the entire suture is dislocated causing hemorrhage and obstruction in the lumen of the coronary ostiums.
Due to all of this, the duration of the surgery is considerably lengthened due to the sutures being hard to make and with little space to use the instruments without distorting the structure of the tube itself.